Such a heat exchanging device is known from DE 39 29 004 A1. This publication shows a heat exchanger with double plates having on inside and outside surfaces profiles that are constructed as beads or webs lying perpendicular to the direction of flow. These webs are arranged one after the other in the flow direction and their height is less than the spacing of adjacent webs. The webs are intended here to bring about turbulence in the flowing medium and thus an improved heat transfer.
DE 38 22 890 A1 shows a cooling arrangement with a blower and a plurality of parallel cooling elements, each comprising elongated cooling webs and gap openings interspersed between them, wherein the cooling webs of every two adjacent cooling elements are offset from one another such that in the direction of flow the cooling webs of one cooling element cover the gap opening of the adjacent cooling element.
DE 198 13 119 A1 shows a turbulence heat recapture device with profiled plates, the profiles of which are inclined alternately one from the other by the same angle from the longitudinal direction of the pressure gradient. The intention thereby is to generate a turbulent flow that improves heat exchanger performance.
Such heat exchanging devices are used, for instance, to cool electronic components such as microprocessors or chips. A distinction is generally made between active and passive cooling units. In active cooling units, subassemblies such as fans or ventilators are used to support the removal of heat with the aid of a fluid stream, or to make it possible at all. The fluid stream thus generated flows through a cooling body that is coupled to a heat source and absorbs heat from it. Known cooling bodies have a rib or column structure and are partially roughened on the surface. The fluid flowing around or through the cooling body thereby absorbs the heat. Air is mainly used as fluid in the cooling of processors. Since air is a very poor conductor of heat, the cooling bodies must be designed to be relatively large in order to have a heat output surface that is large in proportion to the heat intake surface. For this purpose, it is proposed in the prior, not previously published German Patent Application No. 100 41 829 that the heat-output surface be substantially larger than the heat intake surface, which is achieved by a specified structuring in the form of channels and in the form of furrows that are fluidically connected to the channels.
Cooling devices with a substrate through which channels extend are also known from DE 196 19 060 A1 and EP 0 308 576 A2. The channels in those cases can be rectangular or circular.
DE 92 14 061 U1 describes a cooling body whose heat-intake surface comprises ribs and furrows to increase surface area.
One problem for active heat exchanging devices, alongside their large dimensions, is the power requirement for the device for generating the fluid flow. For an effective transfer of heat, a relatively high power consumption and usually a need for space for the corresponding equipment such as a fan result. Another complication is that a good transfer of heat from the heat output surface to the fluid takes place only if the heat output surface has a relatively high flow resistance to the fluid stream. This in turn requires a stronger fan, however.